1. Field of the Invention
The invention relates to a locking and release mechanism for securing a loading/unloading buoy on a vessel, wherein the buoy is of the type to he introduced into a submerged downwardly open receiving space in the vessel, and to be fastened in a releasable manner in the receiving space.
2. Background Information
There are previously known various types of submerged buoy structures wherein locking and release mechanisms of the above-mentioned type are used. For example, from U.S. Pat. No. 4,604,961 (corresponds to Norwegian patent No. 167,906) there is known a vessel having a releasable mooring system wherein the vessel has a through-going deck opening, the lower part of the through opening forming a submerged receiving space for a mooring element in the form of a submerged buoy. In the receiving space there is arranged a rotating body (turret) which is rotatably mounted in the hull of the vessel and is designed for receipt and releasable attachment of the buoy. To this end, the buoy is provided with a hydraulically actuated locking mechanism for attachment to the rotating body.
Since the hydraulically actuated locking mechanism in the known system is arranged on the mooring element or buoy, this requires divers for connection of the control hydraulics. Alternatively, a relatively complicated swivel means must be used. Diver operations in connection with connection and disconnection are time consuming and renders the use of the known system as a transport system impossible, when using shuttle tankers. Further, there is a big risk for faulty operations and damages in case of uncontrolled disconnection. Further, a very substantial disadvantage is that, in case of breakage in the hydraulic system, there is no possibility for connection of a back-up or auxiliary device.
In the known locking mechanism, there are used horizontally movable locking pins which are moved in their longitudinal direction for engagement with an abutment surface on the rotating body. This is an unadvantageous solution, since it results in great edge loads on the locking pins and the abutment surface during disconnection, especially in case of unrelieved emergency disconnection, and thereby to deforming stresses.
It is thus a general object of the invention to provide a locking and release mechanism which is without the abovementioned drawbacks.
A more particular object of the invention is to provide a locking and release mechanism which avoids large edge loads under connection as well as disconnection, also in case of emergency disconnection, and which in addition is self-compensating and results in a uniform clamping, also with an uneven abutment edge for the locking elements.
Another object of the invention is to provide a locking and release mechanism which is fixed in relation to the hull of the vessel, and which therefore does not require any swivel transmissions because of turning movements of the vessel.
A still further object of the invention is to provide a locking and release mechanism which in a simple manner may be supplemented with a safety and/or backup means.